1. Field of the Invention
The present invention relates to a tool-path calculation apparatus for a numerical controlled system and a method for operating the same, and more particularly to the tool-path calculation apparatus with a queue buffer for a numerical controlled system and a method for operating the same.
2. Description of Prior Art
Motion control is the core technique in the precision machining tools, and applications of the motion control includes industrial machines for a position control or a velocity control, and further includes computerized numerical control (CNC) machine tools for a high-precision control. A motion control system is integrated with various software and hardware techniques, so cost, stability, use frequency, maintaining service of the motion control system and even scalability and interoperability of the software and the hardware are important factors for evaluating the motion control system. Furthermore, both position and velocity of all spindles of the machine tool are practically taken into account to determine controlling quality of the machine tool.
The tool paths are defined by a G-code file which is produced through a computer-aided manufacturing (CAM) software. Also, the G-code file is a part of the NC-programming that controls NC and CNC machine tools.
The CNC machine tools mean that the computerized numerical control system is installed in the machine tool, and the computerized numerical control system receives and calculates inputted data and afterward sends commands to control operating conditions, such as spindle rotation, cutting tool replacement, cutting motion, coolant switch, or so on, to achieve expected control.
U.S. Pat. No. 6,772,020 disclosed an arrangement for generating command variables for control loops of a numerically controlled machine that includes an interpolator unit for providing position set points with a defined interpolator scanning rate and a precision interpolator unit. The precision interpolator unit includes a scanning rate converter and a downstream-connected low-pass filter, wherein the precision interpolator unit is arranged downstream of the interpolator unit, which generates command variables at an output side from position set points at an input side for one or several downstream-connected control loops, wherein the precision interpolator unit generates command variables in a time pattern of the control loops with a control loop scanning rate. The command variables for the control loops are implemented to adopt a structure of a two-order filter, and the filter is also designed to match the numerically controlled machine. However, it does not render a higher-order differentiability for resultant path curves. The practicability of the numerically controlled machine is reduced due to high complexity of the command-generating arrangement.
Hence, a tool-path calculation apparatus for a numerical controlled system and a method for operating the same are disclosed to reduce the amount of the sent data and reduce path error.